The inventive concept relates to a complementary metal-oxide-semiconductor (CMOS) pixel or pixel array, an image sensor including the same, and to a method of forming a CMOS pixel or pixel array.
CMOS image sensors are characterized as solid-state sensing devices, whereas charge coupled device (CCD) image sensors are characterized as image sensors having high-voltage analog circuits. CMOS image sensors are less expensive to manufacture and relatively smaller than CCD image sensors and thus tend to consume less power than CCD image sensors. In addition, CMOS image sensors have been dramatically improved in terms of their performance. Therefore, CMOS image sensors are preferred for use in various electronic products including portable devices such as smart phones and digital cameras.
Such CMOS image sensors typically comprising an array of pixels each having a photoelectric conversion element. The photoelectric conversion element generates an electrical signal whose value depends on the quantity of light incident on the pixel comprising the photoelectric conversion element. The CMOS image sensor processes electrical signals so generated by the pixels to synthesize an image. With the recent demand for high-resolution images, the pixels of a CMOS image sensor must be miniaturized.
However, as the pixels become smaller, noise is more likely to occur due to a defect in an isolation film (or an isolation region) for isolating the pixels or elements in a pixel from each other.